Which Feng Shui Theory To Use?

Two days ago, I met a very experienced Geomancer and we were chatting casually on methods we adopt when we do feng shui audit. He asked me, which were the techniques that I know of and have applied, and how accurate were they? I said I know a few, Eight House Theory, Flying Star, IChing Feng Shui, but seldom all the theories I used gave the same answers. He then asked me so which theories were superior?

While I was pondering for a politically correct answer so as not to offend him in relation to his speciality, he quickly continued with his view. He commented that all theories have their strengths and weaknesses and we would have observed that a certain method works for us for a particular period of time but somehow it lose its accuracy after that period (the period maybe a season, a month, a year or longer) and it is different from everyone. His advice was to learn different methods so that we could compare which is the most appropriate method that suit a particular property and stick to the method for that audit..sounds like a good advice, isn't it?